Kotlin using ArgumentCaptor.capture() returns null-CodePudding

I'm pretty new to testing so I might be doing something wrong.I'm trying to capture the values that are passed to a method

    @Mock
    private lateinit var service: TestService


    @InjectMocks
    private lateinit var underTest: UnderTestService

    @org.junit.jupiter.api.Test
        fun `testMethod`() {
            //given
            val var1 = Test.Value
            val var2 = TestClass::class.java
            val var3 = listOf(Entry1(), Entry2())
    
            //when
            underTest.method(var1, var2, var3)
    
            val argumentCaptor = ArgumentCaptor.forClass(String::class.java)
    
            verify(service, times(2)).method(
                argumentCaptor.capture(),
                argumentCaptor.capture()

        )

Here, after doing verify the argumentCaptor.capture() return null for some reason and I don't understand what am I doing wrong?

java.lang.NullPointerException: argumentCaptor.capture() must not be null

I think that it is kotlin related, the signature of the method that I'm trying to get the parameters looks like this

    fun method(param1: String, vararg param2: String?) {
            //do something
  }

CodePudding user response：

MockitoKotlinHelpers.kt can help you here. The capture function provides a way to call ArgumentCaptor.capture()

Example:

verify(service, times(2)).method(
                capture(argumentCaptor),
                capture(argumentCaptor));